ROSS AND THE ROOKIE TOO MUCH FOR DIAMONDBACKS

Monday, Tyson Ross continued what he’s been doing week after week after week, extending a franchise record with his 14th consecutive quality start. Meanwhile, in his major-league debut, Cory Spangenberg did what the Padres hope is just the beginning.

On the same day he was officially promoted from Double-A San Antonio, Spangenberg drove in two runs and made a pair of impressive plays at third base, helping the Padres to a 3-1 victory over the D-backs.

“Definitely a fun day,” said Spangenberg, who went 1-for-4 with what proved the decisive hit. “It was great to get the win.”

Said Ross: “Today was a battle, but Cory had a huge game for us defensively and offensively. Rene (Rivera) was working his tail off behind the plate. It was just a good team win.”

Ross struck out eight over six innings, not allowing a run until his final frame — and then recovering impressively. An inning earlier, Spangenberg had come up with a two-run single, providing a necessary cushion. Before that juncture, Ross’ support had lagged, not that it was anything new.

Indeed, after the season’s first five months, Labor Day unfolded like a tidy encapsulation of the Padres’ uneven campaign.

Offense: maddeningly stagnant, until a second-half surge.

Defense: solid.

Ross: brilliant.

In this series opener, though, a long-awaited variable had arrived. Starting at third and batting eighth was Spangenberg, whom the Padres drafted 10th overall three years ago, in front of Houston’s George Springer and Miami’s Jose Fernandez.

Those two players have already impacted their respective clubs on the big-league level — in Fernandez’s case, with elite production — something the Padres have too rarely seen from their homegrown talents.

Spangenberg, whose rise through the minor leagues was slowed by two concussions, possesses the talent to become an exception. Even if it’s been just one game, that much is clear.

Moments into the top of the first, Spangenberg executed a diving stop to his left, averting an RBI single, and threw to second for a force out. It was just his eighth professional start at third, a position the organization had introduced to him this season to enhance the second baseman’s versatility.

In his first at-bat, Spangenberg looked much like a rookie, hitting a weak grounder directly to short. His speed, an attribute attractive to the Padres three years ago, resulted in a fielder’s choice, averting a double play.

In the top of the fifth, Spangenberg charged a dribbler, bare-handed the ball and fired across his body to end the half-inning. In the sixth, Spangenberg nearly made another diving stop, instead watching a sharply struck grounder sneak under his glove for a single.

Spangenberg’s most substantial moment, however, came in the bottom of the fifth, when the 23-year-old came to the plate with two outs and the bases loaded. The Padres held a precarious 1-0 lead despite a shaky start by Arizona’s Trevor Cahill, who’d walked six of the first 19 batters he faced.

Against reliever Eury De La Rosa, Spangenberg fell behind, 0-and-2. He watched a slider go by for a ball.

On the next pitch, a slow curveball, he singled through the right side, giving the Padres a 3-0 advantage.

“I was just looking for a pitch up in the zone a little bit that I could put the bat on ball,” Spangenberg said, “and I got enough of it to find a hole.”

Uncharacteristically, in the sixth, Ross yielded three consecutive singles, the last scoring a run. He responded by striking out the side on his 114th pitch, this despite tweaking his left knee fielding a comebacker in the previous inning. The Padres will monitor the knee in the coming days, though Ross said afterward he expected to be fine.

“This not only was a great learning experience for him, how to get out of a tough inning when his pitch count’s high,” Black said, “but I felt at that point he was our best pitcher and his stuff was still good. … That was really tough, clutch pitching.”

Following the burgeoning ace’s departure, Nick Vincent, Dale Thayer and Kevin Quackenbush each threw a perfect inning of relief. With Joaquin Benoit down with a sore shoulder, Quackenbush struck out the side, collecting his second save.